1. Field of the Invention
This invention is related to seismic data processing. More specifically, the invention relates to a system for organizing seismic data.
2. Background
Geophysical and geologic study of the subsurface structure of the earth continues to be an important field of endeavor for several reasons. The continued search for producing reservoirs of hydrocarbons, such as oil and gas, is a particularly important motivation for obtaining information about the earth""s subsurface.
Conventional seismic surveying is generally performed by imparting energy to the earth at one or more source locations, for example, by way of a controlled explosion, mechanical impact or the like. Return energy is then measured at surface receiver locations at varying distances and azimuths from the source location. The travel time of energy from source to receiver, via reflections and refraction from interfaces of subsurface strata is indicative of the depth and orientation of the subsurface strata.
The generation of instantaneous phase sections derived from seismic data is referred to in an article by Taner and Sheriff included in AAPG Memoir 26 from 1977, in which it is stated:
xe2x80x9cThe instantaneous phase is a quantity independent of reflection strength. Phase emphasizes the continuity of events; in phase displays . . . every peak, every trough, every zero-crossing has been picked and assigned the same color so that any phase angle can be followed from trace to trace.xe2x80x9d And xe2x80x9cSuch phase displays are especially effective in showing pinchouts, angularities and the interference of events with different dip attitudes.xe2x80x9d
Various phase unwrapping techniques are known, including those disclosed in Ghiglia, Dennis C. and Pritt, Mark D., Two-Dimensional Phase Unwrapping Theory, Algorithms, and Software, John Wiley and Sons, Inc., New York, N.Y., 1998. Methods of obtaining topography from synthetic aperture radar data have also used phase unwrapping techniques.
A long felt need continues to exist, however, for improved systems for organizing, storing and displaying seismic information to assist in the analysis and interpretation of the subsurface structure and geology.
In one embodiment the invention comprises a system for utilizing a geologic time volume to investigate a portion of the earth in which a geologic time is selected and a search is made in the geologic time volume for locations having substantially the selected geologic time. Locations in the geologic time volume having substantially the geologic time are extracted from the geologic time volume. Locations having substantially the selected geologic time may be displayed to facilitate use of the geologic time volume by an interpreter.
In accordance with one embodiment of the invention, the interpreter simply points to a location and the horizon closest to that location is extracted from the geologic time volume and displayed as a map view or as a three dimensional (3D) visualization display.